📄 Description (English)
A weakness has been identified in Tenda A21 1.0.0.0. This affects the function set_device_name of the file /goform/SetOnlineDevName. This manipulation of the argument devName causes stack-based buffer overflow. It is possible to initiate the attack remotely. The exploit has been made available to the public and could be used for attacks.
🤖 AI Executive Summary
A critical stack-based buffer overflow vulnerability exists in Tenda A21 wireless router firmware version 1.0.0.0, affecting the device name configuration function. The vulnerability can be exploited remotely without authentication, allowing attackers to execute arbitrary code and gain complete control of the router. With public exploit availability and widespread router deployment in Saudi networks, immediate patching is essential.
📄 Description (Arabic)
🤖 AI Intelligence Analysis Analyzed: Apr 22, 2026 22:58
🇸🇦 Saudi Arabia Impact Assessment
This vulnerability poses significant risk to Saudi organizations across multiple sectors: (1) Banking/SAMA-regulated institutions using Tenda routers for branch connectivity or backup internet links face potential network compromise and data exfiltration; (2) Government agencies and NCA-regulated entities may experience unauthorized access to internal networks; (3) Healthcare facilities relying on Tenda equipment for medical device connectivity could face patient data breaches; (4) Energy sector (ARAMCO, utilities) using these routers in operational technology networks risks critical infrastructure disruption; (5) Telecom providers (STC, Mobily, Zain) and ISPs face potential network-wide compromise; (6) SMEs and residential users provide entry points for lateral movement into enterprise networks. The remote, unauthenticated nature makes this particularly dangerous in Saudi's interconnected business environment.
🏢 Affected Saudi Sectors
Banking and Financial Services (SAMA-regulated)
Government and Public Administration (NCA-regulated)
Healthcare and Medical Services
Energy and Utilities (ARAMCO, regional utilities)
Telecommunications (STC, Mobily, Zain, regional ISPs)
Small and Medium Enterprises (SMEs)
Residential/Consumer Networks
🎯 MITRE ATT&CK Techniques
T1190 - Exploit Public-Facing Application (remote exploitation of router web interface)
T1200 - Hardware Additions (physical access to router for exploitation)
T1021.001 - Remote Services: RDP (lateral movement post-compromise)
T1059.001 - Command and Scripting Interpreter: PowerShell (code execution)
T1040 - Traffic Capture (network sniffing from compromised router)
T1557.002 - Adversary-in-the-Middle: ARP Cache Poisoning (MITM attacks from router)
T1071.001 - Application Layer Protocol: Web Protocols (C2 communication)
⚖️ Saudi Risk Score (AI)
8.9
/ 10.0
🔧 Remediation Steps (English)
IMMEDIATE ACTIONS:
1. Identify all Tenda A21 devices in your network using network scanning tools (nmap, Shodan queries for Saudi IP ranges)
2. Isolate affected routers from critical network segments if patching cannot be completed immediately
3. Change default credentials on all Tenda devices (admin/admin)
4. Disable remote management features via web interface (System Settings > Remote Management)
5. Restrict access to router management interface (192.168.0.1) to trusted IP addresses only
PATCHING GUIDANCE:
1. Download latest firmware from Tenda official website (verify digital signatures)
2. Backup current router configuration before upgrading
3. Perform firmware update via router web interface (System Tools > Firmware Upgrade)
4. Verify successful update by checking firmware version in System Settings
5. Test network connectivity and device functionality post-update
COMPENSATING CONTROLS (if immediate patching impossible):
1. Implement network segmentation - isolate router management traffic
2. Deploy IDS/IPS rules to detect buffer overflow attempts on port 80/443
3. Monitor for suspicious HTTP POST requests to /goform/SetOnlineDevName
4. Implement WAF rules blocking oversized devName parameters (>256 bytes)
5. Enable router access logs and monitor for unauthorized configuration changes
DETECTION RULES:
- Alert on HTTP POST to /goform/SetOnlineDevName with devName parameter >256 characters
- Monitor for multiple failed authentication attempts to router management interface
- Track firmware version changes on Tenda devices
- Alert on unexpected router reboot or configuration reset events
🔧 خطوات المعالجة (العربية)
الإجراءات الفورية:
1. تحديد جميع أجهزة Tenda A21 في شبكتك باستخدام أدوات المسح (nmap، استعلامات Shodan للنطاقات السعودية)
2. عزل الأجهزة المتأثرة عن القطاعات الحرجة إذا لم يكن التصحيح ممكنًا فورًا
3. تغيير بيانات الاعتماد الافتراضية على جميع أجهزة Tenda
4. تعطيل ميزات الإدارة البعيدة عبر واجهة الويب
5. تقييد الوصول إلى واجهة إدارة الجهاز للعناوين الموثوقة فقط
إرشادات التصحيح:
1. تحميل أحدث برنامج تشغيل من موقع Tenda الرسمي (التحقق من التوقيعات الرقمية)
2. نسخ احتياطي للإعدادات الحالية قبل الترقية
3. تنفيذ تحديث البرنامج عبر واجهة الويب
4. التحقق من نجاح التحديث بفحص إصدار البرنامج
5. اختبار الاتصال والوظائف بعد التحديث
الضوابط البديلة:
1. تطبيق تقسيم الشبكة وعزل حركة إدارة الجهاز
2. نشر قواعد IDS/IPS للكشف عن محاولات تجاوز المخزن المؤقت
3. مراقبة طلبات HTTP المريبة إلى /goform/SetOnlineDevName
4. تطبيق قواعد WAF لحجب معاملات devName الكبيرة
5. تفعيل سجلات الوصول ومراقبة التغييرات غير المصرح بها
قواعد الكشف:
- تنبيهات على طلبات HTTP POST بمعاملات devName تتجاوز 256 حرفًا
- مراقبة محاولات المصادقة الفاشلة المتكررة
- تتبع تغييرات إصدار البرنامج
- تنبيهات إعادة التشغيل غير المتوقعة
📋 Regulatory Compliance Mapping
🟢 NCA ECC 2024
ECC 2024 A.8.1 - Asset Management and Inventory Control (identify all Tenda devices)
ECC 2024 A.12.6.1 - Management of Technical Vulnerabilities (patch management)
ECC 2024 A.14.2.1 - Secure Development and Change Management (firmware updates)
ECC 2024 A.13.1.1 - Network Security Perimeter (network segmentation controls)
🔵 SAMA CSF
SAMA CSF ID.AM-1 - Asset Management (inventory of network devices)
SAMA CSF PR.IP-12 - Vulnerability Management (patch deployment)
SAMA CSF DE.CM-8 - Malware Detection (IDS/IPS rules for exploit detection)
SAMA CSF RS.MI-2 - Incident Response and Recovery (isolation procedures)
🟡 ISO 27001:2022
ISO 27001:2022 A.5.19 - Vulnerability Management
ISO 27001:2022 A.8.1 - Asset Management
ISO 27001:2022 A.8.2 - Information Security Roles and Responsibilities
ISO 27001:2022 A.12.6 - Management of Technical Vulnerabilities and Exposures
🟣 PCI DSS v4.0.1
PCI DSS 6.2 - Ensure security patches are installed within defined timeframe
PCI DSS 11.2 - Run automated vulnerability scans regularly
PCI DSS 2.1 - Always change vendor-supplied defaults
🔗 References & Sources 5
🔗
https://github.com/QIU-DIE/cve-nneeww/issues/6
cna@vuldb.com
Exploit
Issue Tracking
Mitigation
Third Party Advisory
🔗
https://vuldb.com/?ctiid.347180
cna@vuldb.com
Permissions Required
VDB Entry
🔗
https://vuldb.com/?id.347180
cna@vuldb.com
Third Party Advisory
VDB Entry
🔗
https://vuldb.com/?submit.754640
cna@vuldb.com
Third Party Advisory
VDB Entry
🔗
https://www.tenda.com.cn/
cna@vuldb.com
Product
📦 Affected Products / CPE 1 entries
tenda:a21_firmware:1.0.0.0